hibernate的一对一映射-外键映射-单向-mysql数据库

桃扇骨 2022-07-21 00:20 215阅读 0赞

hibernate的onetoone映射分为一对一主键映射-外键映射-单向-mysql数据库

import java.io.Serializable;
    import javax.persistence.CascadeType;
    import javax.persistence.Column;
    import javax.persistence.Entity;
    import javax.persistence.FetchType;
    import javax.persistence.Id;
    import javax.persistence.JoinColumn;
    import javax.persistence.OneToOne;
    import javax.persistence.Table;
    
    /**
     * hibernate 1对1映射
     * 外键映射
     * 单向
     * @author WuJieJecket
     * 
     */
    
    @Table(name="DCLASS")
    @Entity(name="DCLASS")
    @SuppressWarnings("serial")
    public class Dclass implements Serializable {
    	private String classname;
    	private Dstudent dst;
    	/**
    	 * @return the classname
    	 */
    	@Id
    	@Column(name="CLASSNAME")
    	public String getClassname() {
    		return classname;
    	}
    	/**
    	 * @param classname the classname to set
    	 */
    	public void setClassname(String classname) {
    		this.classname = classname;
    	}
    	/**
    	 * @return the dst
    	 */
    	//cascade=CascadeType.MERGE
    	//或者写多个cascade={CascadeType.MERGE,CascadeType.DETACH}
    	//CascadeType.PERSIST 级联保存
    	//CascadeType.MERGE 级联更新
    	//CascadeType.DETACH 未知级联
    	//CascadeType.REMOVE 级联删除
    	@OneToOne(cascade=CascadeType.ALL,fetch=FetchType.LAZY)//级联更新设置，否则Dclass和Sstudent需要单独保存了
    	@JoinColumn(name="fid")//指定主表外键名字
    	public Dstudent getDst() {
    		return dst;
    	}
    	/**
    	 * @param dst the dst to set
    	 */
    	public void setDst(Dstudent dst) {
    		this.dst = dst;
    	}
    	
    	
    
    }

import java.io.Serializable;
    
    import javax.persistence.Column;
    import javax.persistence.Entity;
    import javax.persistence.Id;
    import javax.persistence.Table;
    
    @Table(name="DSTUDENT")
    @Entity(name="DSTUDENT")
    @SuppressWarnings("serial")
    public class Dstudent implements Serializable {
    
    	@Id
    	@Column(name="STUDENTNAME")
    	private String studentname;
    
    	/**
    	 * @return the studentname
    	 */
    	public String getStudentname() {
    		return studentname;
    	}
    
    	/**
    	 * @param studentname the studentname to set
    	 */
    	public void setStudentname(String studentname) {
    		this.studentname = studentname;
    	}
    	
    	
    }

配置文件

<?xml version="1.0" encoding="UTF-8"?>  
<!DOCTYPE hibernate-configuration PUBLIC  
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"  
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">  
<hibernate-configuration>  
  
  
<session-factory>  
  
<property name="connection.driver\_class">  
com.mysql.jdbc.Driver  
</property>  
  
<property name="connection.url">  
jdbc:mysql://localhost:3306/test  
</property>  
  
<property name="connection.username">用户名</property>  
  
<property name="connection.password">密码</property>  
  
<property name="dialect">  
org.hibernate.dialect.MySQLDialect  
</property>  
  
<property name="show\_sql">true</property>  
<property name="format\_sql">true</property>  
<property name="hbm2ddl.auto">update</property>  
<mapping class="hibernate.dfonetoone.Dclass" />  
<mapping class="hibernate.dfonetoone.Dstudent" />  
  
  
</session-factory>  
  
  
</hibernate-configuration>

测试方法

@Test
    	public void testOnetoone(){
    		HIbernateUtil hbu=new HIbernateUtil();
    		Session s=hbu.getSession();
    		s.beginTransaction();
    		
    		Dstudent dst=new Dstudent();
    		dst.setStudentname("小明"+hbu.returnid());
    		
    		Dclass dc=new Dclass();
    		dc.setClassname("语文"+hbu.returnid());
    		dc.setDst(dst);
    		
    		s.save(dc);
    		
    		s.getTransaction().commit();
    		s.close();
    	}